The approach will be a comparison of two groups of infants followed from birth to death or discharge from the hospital. The study group will consist of infants transported from level I or II facilities to a level III facility; the comparison groups will be non-transported infants in level I and II facilities matched by birthweight, gestational age, medical condition, and type of hospital at birth. Charts of newborns weighing less that 2500 grams will be audited at all New York City hospitals. Variation in clinical severity will be estimated using modifications of the lubchenko index and six hour respiratory distress scores. During the first year of the project a feasibility study will be conducted to determine data availability and success in the quantity and quality of the matching process and the proposed analysis plan will be refined. Analysis of variance and regression using both categorical and continuous variables will be conducted. It is expected that non-transported neonates will have a significantly higher mean mortality rate. Additionally it is expected that other variables will have causal impact on mortality rates.